ML20045F247

Suppl Special Rept 1-93-004,summarizing Results of Investigation & Providing Updated Status W/Regard to Repair of Deluge Valve 20 Due to Failure of Latch Arm Gasket. Temporary Repair Package Issued

ML20045F247
Person / Time
Site:	Brunswick
Issue date:	06/30/1993
From:	Jonathan Brown CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1-93-004, 1-93-4, BSEP-93-0098, BSEP-93-98, NUDOCS 9307070133
Download: ML20045F247 (2)

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edEB Carolina Power & Ught Company gene-mwenwjyam Brunswick Nuclear Plant conma,y conespon*nce P. O. Box 10429 Southport N 28461-0429 File: B09-13510C Serial: BSEP 93-0098 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk ,

Washington, DC 20555 l J

BRUNSW1CK NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-325 & 50-324 LICENSE NOS. DPR-71 & DPR-62.

SUPPLEMENTAL SPECIAL REPORT 1-93-004 Gentlemen:

On March 29, 1993, Brunswick Nuclear Plant submitted Special Report (SR) 1-93-004 ,

to the Nuclear Regulatory Commission. The Special Report detailed plans to repair Deluge Valve 20 due to failure of the latch arm gasket. There had been recurring problems with the deluge valve latch arm gaskets and methods for permanent repair / replacement of the Deluge Valve System have been under investigation. The following summarizes the results of the investigation and provides the updated status referenced in Special Report 1-93-004. ,

The original design of the sprinkler systems in the Reactor, Diesel Generator, Service Water and Radwaste Buildings utilized a standard deluge valve actuated by the fire detection system. Brunswick Nuclear Plant has a Primed Pre-action System. The system is primed by a bypass line on the deluge valves. This bypass line allows full system pressure (150+ psig) on the downstream side of the deluge valve. The additional pressure on the downstream side of the valve is the reason for the latch arm gasket failures. The deluge valves were designed for applications with a minimum amount of downstream pressure (20 - 30 psig). The additional pressure does not af fect operability of the existing deluge valves or prevent them from performing their required function as verified by periodic test procedures.

Brunswick Nuclear Plant is currently considering a permanent conversion of the sprinkler system design from a Primed Pre-action System to a Wet Pipe System.

This change would delete the function cf the deluge valves by removing the valve internals arid eliminating the automatic tripping function. This proposal will be submitted through the appropriate management approval cycle.

A temporary repair package (Engineering Evaluation Report 93-0312) has been 9307070133 930630 PDR ADDCK 05000324 p?

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.. issued to return sprinkler systems back to service should failures occur. This  !

repair has'been implemented for three deluge valves and will continue to be in ,

place during the. development and implementation of the permanent design change.

Implementation of the permanent design change will be scheduled in accordance1 i with the site priority system in order to integrate this change into other work ,

activitins associated with the fire protection system.  ;

~i Yours very truly, >

. M. Browni Unit 1 Plant Manager.

JFM/jfm  !

Enclosure:

cc: Mr. S. D. Ebneter Mr. P. D. Milano [

BSEP NRC Residents Office t l

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